This invention relates to microwave generators used for household electronic ovens and the like and, more particularly, to microwave generators having a function of controlling microwave energy supplied to an electronic oven.
In the prior art microwave generator, the microwave energy produced from a magnetron is controlled by detecting the phase in each cycle of, for instance, a 50-Hz commercial alternating current voltage and turning on an SCR inserted in a power source circuit for the magnetron. However, in such a microwave generator the magnetron is energized with a high voltage obtained by stepping up the same commercial alternating current voltage through a transformer, that is, in such a power control system based on the phase angle control the SCR is turned on at another phase then the zero phase of the source voltage. Therefore, the voltage supplied to the magnetron rises very sharply, thus giving rise to noise generation from a magnetron oscillation circuit.